how to fix BMW 3 Series G20/G21 (2019-2024) remote start not working properly?

BMW 3 Series G20/G21 (2019-2024)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

4 min read

603 words

Problem Statement

The remote start feature on a BMW 3 Series G20/G21 (2019-2024) is not functioning correctly, leading to issues with starting the vehicle from a distance.

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical components.
•Allow the vehicle to cool down before inspecting any engine components.

Symptoms

•Remote start fails to initiate when activated.
•Engine starts briefly and shuts off after a few seconds.
•Warning lights illuminate on the dashboard after attempted remote start.
•Vehicle does not respond to the remote start command at all.
•Check control messages appear on the vehicle's display screen.

Diagnostic Steps

1
Verify that the key fob battery is fully charged and functional.
2
Check the vehicle's battery voltage to ensure it's above the minimum threshold.
3
Scan the vehicle’s onboard diagnostic system using an OBD-II scanner for any error codes.
4
Inspect the remote start system's fuses and relays for continuity and proper operation.
5
Ensure that all doors, trunk, and hood are securely closed as open sensors can disable remote start.
6
Confirm that the vehicle is in 'Park' mode; remote start may not work if in other gear positions.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Flathead screwdriver
•Socket set

Parts Required

•Key fob battery (CR2032 or equivalent)
•Replacement fuses (if necessary)

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Symptoms

•Remote start fails to initiate when activated.

•Engine starts briefly and shuts off after a few seconds.

•Warning lights illuminate on the dashboard after attempted remote start.

•Vehicle does not respond to the remote start command at all.

•Check control messages appear on the vehicle's display screen.

Diagnostic Steps

1
Verify that the key fob battery is fully charged and functional.
2
Check the vehicle's battery voltage to ensure it's above the minimum threshold.
3
Scan the vehicle’s onboard diagnostic system using an OBD-II scanner for any error codes.
4
Inspect the remote start system's fuses and relays for continuity and proper operation.
5
Ensure that all doors, trunk, and hood are securely closed as open sensors can disable remote start.
6
Confirm that the vehicle is in 'Park' mode; remote start may not work if in other gear positions.

Solution

1. Preparation

Gather necessary tools and parts.
Ensure the vehicle is parked in a safe location with enough space around it.
Disconnect the battery to avoid any electrical issues while working on the vehicle.

2. Key Fob Battery Replacement

Identify the battery type (usually CR2032).
Use a small flathead screwdriver to gently pry open the key fob.
Remove the old battery and insert the new one, ensuring correct polarity.
Snap the key fob back together.

3. Battery Voltage Check

Reconnect the vehicle battery.
Use a multimeter to check the voltage of the vehicle battery; it should be above 12.6 volts.
If the voltage is low, charge or replace the battery as necessary.

4. Inspect Fuses and Relays

Locate the fuse box (refer to the owner's manual for exact location).
Check the fuses related to the remote start system; replace any blown fuses with the same amperage rating.
Test the relays associated with the remote start for proper operation.

5. Sensor Checks

Inspect all door, hood, and trunk sensors to ensure they are functioning correctly.
If any sensors are faulty, replace them to ensure the vehicle recognizes that all access points are secured.

6. Gear Position Verification

Confirm that the gear lever is in the 'Park' position.
If the vehicle is not in 'Park,' shift it to the correct gear and attempt to use the remote start again.